1. Field of the Invention
This invention relates to a method of preventing load reversals in weld joints. Specifically, there is set forth a method for preventing the load reversals in a weld joint between a suspension hanger bracket and an automotive axle.
2. Description of the Prior Art
The current state of the art in mounting tandem drive axles to heavy trucks and other large on and off highway vehicles utilizes axles which incorporate suspension hanger brackets. The hanger bracket captures the suspension member used in the suspension system of the vehicle. The hanger brackets are typically welded to the drive axle housing intermediate its end and the differential case at its center. The typical axle of this type is shown in FIG. 1.
In normal operation, the suspension system of the vehicle imparts vertical and horizontal loads to each of the hanger brackets. It has been found that in order to meet design criteria, no failure of the hanger bracket weld by the impartation of one million load reversals, it was necessary to increase the amount of horizontal bracket weld (fillet size and length) or utilize the set screws of the present invention.
It has been found that with a normal hanger bracket design, a lateral load produces a highly stressed area around the bracket weld shown in FIG. 2 at X and Y. If the lateral load is reversed, the stress is reversed, producing alternate compressive and tensile stresses. This type of loading, reversing bending, it the most unfavorable for extended fatigue life.
By the use of the concept of the present invention, the stresses at points X and Y can be prevented from reversing thereby dramatically extending fatigue life and thus provide an alternate way of extending the fatigue life of the hanger bracket weld.